/ , c I. •300 VICKERS

MECHANISM MADE EASY

GALE & POL DEN LTD FULLY ILLUSTRATED LONDON ALDERSHOT PRICE 1/6 NET AND PORTSMOUTH PER POST I /8 BOOKS SPECIALLY RECOMMENDED

s. d. MIiitary Map Reading, Complete Gulde to. 10th Edition ... 4 6 (By Post, 4/10) CONTENTS.-Maps and Map Readlng--Conventlonal Slgn-ldantlflcation of ·300 VICKERS Points on Map-Seal-HUI Features: Contours,-HIII Features: Gradients and Sectlou-HIII Features: Vlslblll~Topo&raphical Term-The Prismatic Compass -S.ttlns a Map: Flndlns One• Position on a Map-Enlargements and Aeld Sketchlnc-Traverslnc or Prismatic Compus Sketchrnc--Flnding True North: Note on the HorJzoMal Clock Code. Lectures on Battle Training. By Labore. Profusely illustrated MACHINE GUN with photographic plates and line drawings (By Post, 1/8) I 6 CONTENTS.-The Prismatic Com~uerrilla Warfare-Patrols-Night Patrols and Cout Landin-Improvisation-The Sand Table and Cloth Model­ Road Bloc~nlplng-The Individual and Section Stalks-Cover and Camouflage MECHANISM MADE EASY -Booby Traps, Eleven More Lectures on Battle Training. By Labore. Fully illus­ trated with photographic plates and line drawings (By Post, 2/2) 2 0 CONTENTS.-Care of Ar~Zeroing-Flre Control-Practical Theory­ -Oestruction of Grenade " Blinds "-The Grenade-Appendix- Coaching--Groupln1 and Application Targets-Miniature Rang-Night Firing -Characteristics. Questionnaire: 375 Questions and Answers on Training. fully 3rd Edition. By Major W . P. Lousada, M.C., late Royal Norfolk Regiment •.. .•• ...... (By Post, 1/8) 6 illustrated CONTENTS.-Musketry-Flre Contrc,I-Scouts and Patrols-Judging Distance and Fieldcrafc-Grenad-Automatlc -Gas-Reports and Messages­ Mlscellaneous Questions and Answers for Battle Platoon and Battle Squad Com­ manders and N.C.Os.-Appreclatlon of a Sltuadon. How to Teach Battlecraft. By Capt. R. Humphrey and Capt. D. ArdiJZOne, Instructors, No. 2 G.H.Q. School. Fully illustrated (By Post, I /2) I 0 CONTENTS.-Personal Concealment-Personal Movement by Day­ Personal Movement by Night-Selection of Line of Advance-Tactical Cross­ Inc of Obstacl-Observatlon Training-Selection of Fire Positions. Notes and Skeleton Orders for Junior Commanders. On linen-lined folding card for pocket ..• (By Post, -/7) 0 6 I Went on a Course. By Q. One. Illustrated. (By Post, 1/8) I 6 This book sets out all the pitfalls which face the potential student " warned for a course." It should prove Invaluable and a creat preliminary step to securing that elusive " D." It Is profusely Illustrated with amusing pen sketches which not only e nlighten the text but give point co the advice In t he book. Fleldcraft and Stealth. The Training of the Soldier in Stalking, Crawling and Patrolling, By Lieut.-Colonel N. A. D. Armstrong, O.B.E., R.M., Commandant Royal Marines Snipers' School Fully illustrated with 44 Photographic lllustra• tlons and Diagram's .. . •. . . •. ••• .. . •• • •• . 1 0 CONTENTS.-Method of Conducting a Practical 0emonstratlon-Openlnc Talk-Demonstration without Arms-Stalking with a -Stealth Patrol­ Demonstration to Illustrate Progressive Training-Final Demonstration: Individual Stal~cout v. Scout. A LDERSH O T Fleldcraft, Sniping and Intelligence. 5th Edition. By Lieut.­ GALE & POLDEN LIMITED Colonel N. A. D. Armstrong, O.B.E., R.M., Commandant The Royal Marine Snipers' School. Fully Illustrated with plates and One Shilling and Sixpence (net) diagrams ... •.• ••• .•. ..• (By Post, 6/6) 6 0 Notes on Individual Fleldcraft. Contains practical and up-to­ (By post, 1/8) date methods for both day and night operations. Fully Illustrated with half-tone plates· •.• •.. .•• •.• (By Post, 1/2) 0 PUBLISHED BY GALE & POLDEN LIMITED Contents

PAGE Publishers' Foreword GENERAL DESCRIPTION 4 MECHANISM 9 This book is no. meant to replace the official publications on the gun, but rat~er to be read in conjimction with them BACKWARD MOVEMENT OF MECHANISM 8

FORWARD MOVEMENT OF MECHANISM 10 This booklet on the Vickers Machine Gun was originally written for the Home Guard, STRIPPING 14 and it describes and illustrates the .300 calibre SERVICING THE GUN-REPAIRS AND AD- gun, with which they are armed. JUSTMENTS 20 By studying this handbook with the gun by SIGHTS. 24 his side, so that the actual parts of the gun may be referred to as they are mentioned in TRIPOD MOUNTING 26 the text, the reader will find that he will be FIRING THE GUN 28 able very quickly to grasp the names of all the various parts of the gun and the mechanism, KINDS OF FIRE 29 and to strip and handle the gun and prepare FIRING 31 it for firing in a surprisingly short time. BEFORE FIRING 31

Gale & Polden Ltd. DURING FIRING LONDON & ALDERSHOT AFTER FIRING • 33

IMMEDIATE FOR STOPPAGES 34

USEFUL NOTES 36

WATER CONSUMPTION 36

Printed in Great Britain by Gale €, Polden Ud., Aldershol 1944 P-569 ·300 VICKERS MACHINE GUN GENERAL DESCRIPTION PRINCIPLE OF OPERATION The Vickers Machine Gun is recoil operated. 'rt is fed by means of an ammunition . It is water cooled. In recoil operation of automatic weapons, often the energy required to operate the mechanism is entirely furnished by the rearward force of the expanding gases of the exploding powder charge. In the Vickers Machine Gun the motive power given to the recoiling mechanism to drive it to the rear is derived partly in this manner and partly by the powder gases which after the exit of the bulle•t impinge on the front cone of the ball firing attachment and rebound violently against the front face of the muzzle cup. At the moment the explosion takes place the breech is firmly locked against the base of the in the,chamber. The first movement rearward of the recoiling portion of the gun unlocks the breech and the recoiling mechanism is free to move to the rear, and by means of various springs, cams and levers, the necessary mechanical operations are performed whereby the empty case is extracted and ejected, the succeeding live round is extracted from the ammunition feed belt and is fed into the chamber, the gun is cocked, the breech is locked and gun is ready to fire. Once the gun has been loaded with a fully loaded ammunition Plate I ·300 VICKERS MACHINE GuN belt and cocked by hand for the first round, the gun is entirely SIGHTS automatic and will continue to fire round after round so long as A blade foresight is provided and a backsight adjustable for the thumb-piece is pressed, and will stop immediately the windage and elevation is fitted. (See also page 24.) thumb-piece is released or there are no more rounds in the ammunition belt. DATA Weight of gun (water jacket empty) 33¼ lbs. COOLING SYSTEM Weight of gun (water jacket filled) 42 lbs. The heat generated by the continuous firing of the gun is Weight of ammunition belt (loaded 250 absorbed by the water contained in the water jacket which rounds MI ammunition) ... 14¾ lbs. surrounds the barrel, thus the barrel is prevented from over­ Weight of tripod ... 52 lbs. heating. Length of barrel ...... 24½ ins. Muzzle velocity, .303 Mark VII ammuni- TRIPOD MOUNTING tion 2,440 ft. per sec. The gun is mounted on a tripod. The direction and elevation Weight of bullet, .303 Mark VII ammuni- of the gun can be varied at will by the firer by means of the tion 174 grains. elevating and traversing mechanism and movements provided Muzzle velocity, .300 Ml ammunition 2,700 ft. per sec. in the tripod mounting. Weight of bullet, .300 MI ammunition 150 grains. Cyclic (approx.) 500 rds. per min. 4 MECHANISM The action of the mechanism will be the more easily followed and learnt if the gun is loaded with an ammunition belt filled with a number of dummy cartridges and the gun should be manipulated to demonstrate the various actions of the mechanism as described in the following text. N.B.-In demonstrating the working of the mechanism with dummy cartridges, the function of the recoiling portions will be the more easily manipulated if the fuzee box and spring is removed. (See" Stripping," p. 14, para. 5.)

TO LOAD THE GUN (1) Open the shutter. With the bullets of the dummy cartridges to the front, pass the tag end of the ammunition belt (loaded with dummy cartridges) through the feed block from the right. Grip the tag end of the belt protruding through the left side of the feed block with the left hand. (2) Grasp the crank handle with the right hand and pull it on to the roller ; and with it so held, the left hand grasping the tag end of the belt should give it a sharp pull to the left as far as it will go. (3) Let go the crank handle. The first cartridge is now gripped between the upper and lower portions of the gib at the top of the extractor. (4) By pulling the crank handle back on to the roller again, Plate JI giving the belt another sharp pull to the left and letting the crank handle go forward again the first cartridge will be with­ 1 Barrel casing. 14 Safety catch. 2 Foresight. 15 Thumb-piece. drawn from the ammunition belt and positioned in the chamber 3 Foresight protector. 16 Roller. ready to be fired, and the succeeding round will be gripped by 4 Muzzle attachment. 16a Elevating pin. the gib in the upper part of the extractor. 5 Condenser tube. 17 Shutter catch. 6 Screwed plugs. 17a Check lever bracket. The gun is now cocked and ready to fire. 7 Front cover. 18 Crosshead. 8 Rear cover. 19 Socket (tripod). FIRING THE GUN 9 Check lever. 20 Tripod front legs. (5) On raising the safety catch and pressing the thumb-piece of 10 Crank handle. 21 Rear leg (tripod). 22 Elevaring hand wheel. the firing lever, the firing lever pawl pushes the bottom end of 11 Breech casing. 12 Backsight. 23 Ammunition box. the trigger bar lever forward. Thereby the head of the trigger 13 Traversing handles. 24 Ammunition belt. bar lever moves to the rear which, being engaged with the trigger bar situated in the rear cover, draws the latter to the rear. The forward end of the trigger bar being in engagement with the trigger in the lock, the trigger moves to the rear, releasing the striker, which flies forward to explode the cap of the car­ tridge in the chamber. 7 6 right. The top pawls are thus driv~n to th~ rig~t and ride BACKWARD MOVEMENT OF THE MECHANISM over and engage behind the succeedmg cartridge m the belt, The backward movement of the mechanism provides the fallowing which is held in place by the bottom pawls. functions :- THE LOCK (A) The spent case of the fired round in the chamber is extracted. Extractor (B) The succeeding live round is withdrawn from the ammuni­ tion belt and positioned ready to be loaded into the chamber on Cover ramps the next movement forward of the mechanism. Gib (c) The striker is cocked. Side levers (D) The fuzee spring is extended ready to reassert itself to drive Extraction of empty case forward the recoiling mechanism again. Positioning of succeeding round (9) During the backward movement of the lock the extractor MUZZLE ATTACHMENT draws the live round from the belt and the empty case from the Recoiling portions of the mechanism chamber. The horns of the extractor ride along the top of the (6) The explosion of the charge causes a backward pressure on solid cams in the sides of the breech casing, and when they clear the lock,' and the gases which follow the exit of the bullet the ends of these cams (the cartridge is now withdrawn clear of from the barrel at high pressure impinge violently against the the belt) the ramps in the rear cover force the extractor down­ front cone of the muzzle attachment, from which they rebound wards, bringing the cartridge into alignment with the cham~e~. to strike the front face of the muzzle cup. l'hese two forces As the extractor drops the empty case usually falls off ; If It drive the barrel and recoiling portions to the rear approximately does not it will be forced off when the extractor rises on the lock one inch. going forward home, by striking the ejection seating in the barrel casing. The live cartridge is held in position in the extracto~ by BACKWARD ROTATION OF T HE CRANK the gib, the bottom projection of which prevents the cartridge (7) This backward movement of the recoil causes the tail of the from slipping down the extractor face. crank handle to roll against the roller, thus rotating the crank which causes the fuzee to wind the fuzee chain and extend the COCKING ACTION OF THE LOCK fuzee spring, at the same time driving the lock to the rear. The Lock spring momentum imparted to the lock, crank and crank handle by the Trigger recoil causes the crank handle to continue to roll against the Tumbler roller, which, together with the assistance of the pull imparted Sear by the exrended fuzee spring, forces the recoiling portions for­ (ro) The backward rotation of the crank causes the conn~cting ward again with the exception of the lock, which continues its rod and side lever head to move upwards ; the latter bearing on backward movement for a short distance before it joins in the the tail of the tumbler rotates it, thus forcing the firing pin to forward movement. the rear. ACTION OF THE FEED BLOCK The long arm of the lock spring be~rs against the projecti?n of the firing pin. The continued rotation of_the tumbler on. Its Top and bottom pawls axis withdraws the firing pin, thus compressmg the lock sprmg Withdrawing of succeeding round from ammunition belt until the nose of the trigger, actuated by the short arm of !he (8) During the backw;rd movement of the mechanism the stud lock spring, is forced over the bent of t~e tumbler. The firmg of the bottom lever of the feed block located in its recess in the pin is withdrawn still further back until the bent of the s~ar, prolongation of the left side plate is forced to the rear, carrying actuated by the sear spring, springs into the bent of the firmg with it the bottom lever which, connected with the top lever, pin, thus retaining it and preventing it from flying forward. carries the latter to the right, which carries the slide to the

9 8 FORWARD MOVEMENT OF THE MECHANISM The forward movement of the mechanism provides the following The side levers act on the extractor levers which raise the functions:- extractor. The gib releases its hold of the base of the live round (A) The fuzee spring reasserts itself, thus driving the recoiling as it is depressed against its spring and forced to recede into the portions forward. face of the extractor. (B) The succeeding live round is fed into the chamber, and the The extractor grips the live round positioned in the feed next round in the ammunition belt is positioned in the feed block ; the gib springs forward to grip the base ofthis round to block and gripped by the extractor, ready to be withdrawn on position it correctly in the extractor prior to its withdrawal on the next rearward movement of the mechanism. the next rearward movement of the lock. (c) The breech is locked. Should there be no cartridge in the belt for the extractor to (n) The trigger bar being engaged with the trigger, the gun grip when it has reached its highest point, it would fall and the is ready to fire on the thumb-piece being pressed. horns of the extractor would foul the solid cams in the breech THE FEED BLOCK casing on the commencement of the next backward movement of the lock. To prevent this, springs in the side plates are pro­ (11) During the forward movement of the mechanism the feed vided which engage in slots in the sides of the extractor and hold block mechanism is actuated by the stud of the bottom lever it in its highest position. being in engagement by means of its stud in its recess in the prolongation of the left side plate. When the recoiling portions Sear return forward to their original position the bottom lever of the Firing pin feed block is thus moved forward, causing the top lever and slide to move to the left. The slide carries the top pawls to the Trigger left, which brings the next live round in the ammunition belt, Automatic fire behind which these pawls are engaged, into position against the As the lock reaches its fully forward position the side lever head cartridge stops, ready to be gripped by the extractor. is forced by the connection rod slightly below the horizontal, when it depresses the sear, which disengages from the firing pin, FORWARD ROTATION OF THE CRANK allowing the firing pin to move forward slightly so that the nose Fuzee spring action of the trigger engages the bent in the tumbler. (12) When the force of the explosion has been expended, the In automatic fire the pressure on the thumb-piece is retained, fuzee spring, which has been extended during the backward thus the nose of the trigger is held clear of the bent of the movement of the mechanism, reasserts itself and through the tumbler and the firing pin will be free to spring forward under fuzee chain and link rotates the crank in a forward direction, the compression of the lock spring, when the side lever head thereby the connecting rod and side lever head drives the lock depresses the sear, thus firing the cartridge. The depression of forward. the sear is timed so that the firing pin cannot be released until the lock has fully closed and is in the firing position. FORWARD MOVEMENT OF THE LOCK Extractor The gun will continue to fire automatically in this way shot after shot until the pressure on the thumb-piece is released or Side lever there is no more ammunition in the belt. Gib . Insertion of live round into chamber TO UNLOAD THE GUN (13) The extractor carrying the live round, correctly positioned Pull the crank handle on to the roller twice ; this clears the by the gib, feeds it into the chamber by the forward movement two cartridges on the face of extractor. Raise the finger plate of the lock. of the bottom pawls at the same time depress the top pawls ; this frees the belt which can now be withdrawn.

II MOVEMENTS OF THE LOCK ILLUSTRATED The plates opposite serve to show clearly the movements of the lock. The internal mechanism has been taken out of the gun ; the ammunition belt and fuzee spring are omitted for clarity.

Plate 3 (top) Plate 3 shows the lock fully forward home, having inserted the live round in the chamber. The side lever head is in the horizontal position and is seen in contact with the sear, just prior to its finally moving slightly below the horizontal position when it depresses the sear, and presuming pressure on the thumb-piece is maintained, this would allow the striker to fly forward and fire the round in the chamber. 3 The side levers have acted upon the extractor levers which have raised the extractor to its highest position. The extractor in its movement upwards has gripped the succeeding round in the ammunition belt.

Plate 4 (centre) Plate 4 clearly shows the lock in its rearmost position. The backward rotation of the crank is completed, and the tumbler is shown cocked. The side lever head is raised, thus the side levers are disengaged from the extractor levers; thereby the extractor is free to take up its lowest position to allow the live cartridge, correctly positioned in the extractor by the gib, to be brought into alignment with the chamber. The empty case shown in the illustration on the top of the extractor usually falls off when the extractor drops.

Plate 5 (bottom)

In Plate 5 the forward rotation of the crank is nearly completed. 4 The side levers are in engagement with the extractor levers, which have just started raising the extractor. The live cartridge shown in Plate 4 has been fed into the chamber, and the empty case of the previous fired round which has stuck on the extractor will be forced off when the extractor rises to its highest po1,ition. Tumbler is cocked. Sear is up as its bent has engaged with the firing pin bent. •

12

5 26 I

STRIPPING ,al N 21,. First ensure that the gun is unloaded, barrel casing empty, and 35 the shutter open. 28 I ,,,,1,,uu,11"""""'''""111111111111111•! ~ LOCK ""\ I ' (r) Raise rear cover. 30A 30 43B 43c ~ 36 (2) Pull crank handle on to roller, see that extractor drops. I I. (3) Place a finger between extractor and extractor stop and lift • ~ lock ; at the same time allow the crank handle to move forward 43D 391 slowly until the lock is released from the side plates. Lift lock 44 clear and give the lock one-sixth of a turn and lift out. Lower ! crank handle on to check lever so that the connecting rod lies !l!Ilttfll, forward. Close rear cover. 45 • _, FEED BLOCK (4) Raise the front cover and lift feed block out. t FUZEE SPRING AND BOX I 146 47 4 (5) With the left hand grasp the fuzee box near the front and push forward until the sockets on the fuzee box are clear of their retaining studs. Disconnect fuzee spring from fuzee chain. Plate VI Remove fuzee box and spring. FUZEE 4 Muzzle attachment front 38 Crank shaft. cone. 39 Cork plug. (6) Turn the fuzee until the lugs on the stem are free, withdraw ro Crank handle. 40 Crank. fuzee and chain. IDA Tail of crank handle. 41 Connecting rod. IOB Knob of crank handle. 41A Stem of connecting rod. MUZZLE ATTACHMENT 16 Roller. 42 Crank handle fixing pin (7) Withdraw split pin and give outer casing one-sixth turn, I 6A Roller collar. screw. r6B Roller-retaining oin. 43 Right side plate. when it can be removed. Unscrew and remove the muzzle cup, 25 Rear cross-piece T-pin. 43A Left side plate. unscrew front cone (unscrew and remove gland and·· packing 26 Fuzee spring box. 43B Prolongation of left side if necessary). 27 Feed block. plate. 28 Right and left slides. 43c Recess in 43B for stud of RECOILING PORTiONS 29 Fuzee. bottom feed lever. · (8) Raise rear cover. Unscrew and remove T fixing pin and 29A Fuzee chain. 430 Left side plate spring for 60. 30 Fuzee spring. 44 Barrel. lower the rear cross-piece. Remove the right and left slides. 30A F uzee spring hook. 45 Cannelure in 44 for asbestos Draw out recoiling portions-i.e., side plates, crank !Ind con­ 35 Fuzee spring adjusting packing. necting rod and barrel. Disconnect the left side plate from the screw. 46 Muzzle attachment cup. barrel. Remove the right side plate (together with crank handle, 36 Asbestos string packing. 47 Muzzle,r}and. crank and connecting rod) from the barrel. 37 Lock. ROLLER (9) Remove split pin, collar and roller. Parts now stripped (r to 9) from the gun are shown m Plate VI.

14 15 5'° DETAIL STRIPPING

DETAIL STRIPPING THE LOCK (10) The lock will be found to be cocked when removed from the gun, but check to see that it is cocked. Force out the side i'+51 52 53 56 lever split pin and ·axis bush. Remove the side levers, the extractor levers and the extractor. Remove tumbler axis pin, remove tumbler. Depress sear, thus releasing lock spring. Remove trigger axis pin, when the trigger and lock spring can .J ( be removed. Press sear downwards and remove firing pin and ~ I I I I I I I I sear and sear spring. 63 64 65 66 67 68 (11) To remove gib, push out gib spring cover, remove gib spring and gib. ;=i ' j= 69 -r70 r All the parts of the lock as stripped and described above (10 73A 71 72. and 11) are shown in Plate VII. \ To reassemble the lock. ... 1~· • I I (12) Insert sear, spring downwards. Ensure that sear jaws 73 74 75A 75 engage sear pivot. Insert firing pin in its grooves. Insert tumbler and tumbler axis pin. Insert trigger and trigger axis pin. Replace gib, its spring and cover in position on extractor and slide on reassembled extractor. Replace extractor levers, Plate VII LOCK STRIPPED, SHOWING PARTS side levers, and insert bush and split pin. With sear depressed by 37 Lock casing. 63 Tumbler. side lever head, hold trigger back and press down tumbler. 50 Side levers (pair). 64 Trigger. Insert lock spring, long arm towards extractor, and force down­ 5 r Side lever head. 65 Lock spring. 52 Lugs on side levers for 54. 66 Gib spring cover. wards and home. 53 Flanges of lock casing. 67 Gib spring. CAUTION.-The firing pin should never be released 54 Slots in lock casing for lugs 68 Gib. unless the extractor is up against the top stop, so as to on side levers (52) . 69 Side levers axis bush. 55 Bearing on lock casing for 70 Split-pin keeper for side ensure that upon release the striker is in alignment and side levers (50). levers axis bush. protrudes through the striker hole in the extractor. 56 Interruptions in flanges of 7r Tumbler axis pin. lock casing. 72 Trigger axis pin. FEED BLOCK 57 Extractor stop of lock casing. 73 Sear. 58 Extractor. 73A Sear bent. 59 Horns of extractor. 74 Sear spring. (13) Force out the split pin which fixes the top and bottom 60 Grooves in extractor for side 75 Firing pin. levers together. Separate the top and bottom levers. Remove plate springs. 75A Firing pin bent (to engage the slide, top pawls aad spring. Draw out bottom pawl axis pin 6r Shoulders of extractor for sear bent). and remove bottom pawl and spring. side lever (78). 77 Bent of extractor lever for 6,2 Hole in extractor for firing side levers. The feed block showing all the parts stripped as described above pin (75). 78 Extractor lever (right). (12 and 13) is shown in Plate VIII, p. 19. To reassemble the feed block reverse the aboi•e.

16 17 81 82 If necessary the foilowing can be stripped; those operations Bf marked by an asterisk (*) should only be performed by an armourer. I *CRANK HANDLE (14) After removing right side plate (see 8 above) the crank handle may be removed by taking out the screwed fixing pin and n driving off the crank handle by means of a drift and mallet, I r83 *CHECK LEVER 84 27 (15) The keeper pin should be driven out from the underside, when the check lever can be removed. 90 REAR COVER LOCK ~91 (16) Remove axis pin by unscrewing. Remove cover lock and t + /~ spring.

TRIGGER BAR ~89~ (17) Remove spring and withdraw trigger bar. 1 *FRONT AND REAR COVER \/ l ~86 87 88 92 (18) Remove the keeper pin and check nut and force out the joint pin.

*REAR CROSSPIECE

(19) Remove keeper pin and check nut and force out joint pin. Plate V 111 FEED BLOCK STRIPPED

*FORESIGHT 27 Feed block. 86 Finger plate of bottom 80 Feed block slide. pawls. (20) The correct zero position for the foresight should first be 81 Top pawls spring. 87 Axis pin for bottom pawls. carefully marked so that it can be replaced in exactly the same 82 Top lever. 88 Top pawls thumb grips. position. The foresight is removed by driving it out of its 8 3 Stud of top lever for feed 89 Top pawls (rear). block slide 80. 90 Top pawls (front). dovetail groove in the foresight block. It should be driven out 84 Bottom pawls spring. 91 Bottom lever. from left to right-i.e., driven through the right-hand opening 85 Bottom pawls. 92 Split pin for fixing top and in the foresight protector. bottom feed block lever.

STEAM TUBE t (21) CAUTION.-This should not be removed if the valve is free. With the gun removed from the tripod, place the gun upright, muzzle up, so that gun will stand on the rear end of the breech casing. Remove the keeper screw and unscrew the steam tube.

18 19 7 I TO REASSEMBLE THE GUN Reverse the foregoing stripping operations. Pay particular care to the following :- (A) With the cartridge guide slot uppermost (the cut in trunnion block at entrance to chamber) replace side plates and make certain that they are properly home on the barrel trunnions 0 -===~ 104 and crank shaft. Force must not be used as burrs on the ""' crank shaft might occur. If the recoil portions do not go home properly, they must be withdrawn and checked to see that the side plates are properly assembled before reassembling again. I t-108 (B) When replacing the gland of the muzzle attachment on the gun, see that it is screwed right home to abutt casing ; if this is not done the muzzle cup is likely to foul the muzzle gland when the Barrel recoils, with resultant damage to J-109 11I I the muzzle cup. The split pin which fixes the outer casing to 1-\ the outer attachment of the muzzle gland should be fixed in the ' 25 105 107 107A top hole. (c) When reassembling the steam tube, see th~t the acorn end is inserted into its seating in the barrel casing. This is the more Plate IX easily done by keeping the acorn end in contact with the adjacent 7 Front cover. channel formed by the corrugation of the barrel casing. When 8 Rear cover. 1 ~~ } Hooks of rear cover lock. in the correct position, the tube will screw home quite freely. I 3 Rear cross-piece grips. 101 Trigger bar. 14 Safety catch. 102 Front cover catch. SERVICING THE GUN-REPAIRS AND 25 Rear cross-piece T-pin. 103 Front cover catch plunger 93 Hooks of front cover catch. 104 Joint covers screwed pin. ADJUSTMENTS 94 Extractor stop. 105 Rear cross-piece screwed There are certain repairs and adjustments which the gun will 95 Grooves in rear cover for joint pin. require from time to time and which gunners should be capable ribs on breech casing. 107 Firing lever. 96 Rear cover ramps. 107A Firing lever pawl. of carrying out by themselves. 97 Rear cover lock spring. 108 Trigger bar lever. CORRECT LENGTH OF CONNECTING ROD 98 Rear cover lock. 109 Safety catch axis pin. It is important that the connecting rod should be of the correct length, as upon this depends the correct space between the face of the extractor and the base of the live round in the chamber. Connecting Rod too Short If the connecting rod is too short the space will be too great and 1 · the base of the cartridge will not be firmly supported on the explosion of round, which may result in a bulged or separated case. Connecting Rod too Long If the connecting rod is too long the lock will not go fully for­ ward home ; the side lever head will therefore not depress the sear and the gun cannot fire.

20 21 TO ADJUST AND CARRY OUT THE CORRECT Breech End Packing ADJUSTMENTS OF THE CONNECTING ROD Should water leak at the breech end, empty the barrel casing and withdraw the recoiling portions. A piece of asbestos string To adjust and carry out the correct adjustments of the connect­ soaked in oil should be wound into the cannelure of the barrel. ing rod, the following should be done :- It should be pressed in with the point of a screw-driver or other ( 1) Remove the lock. sharp instrument until the cannelure is full. (2) Remove the fuzee spring. The packing should now be oiled and smoothed down flush with the barrel. Reassemble the recoiling portions. (3) Crank handle should be placed nearly vertical. Muzzle Gland (4) Place washer No. 1 on outer face of adjusting nut. Should water leak at the muzzle, stand the gun upright, remove (5) Replace the lock in the rear position. muzzle attachment, muzzle cup, and unscrew the muzzle gland. ( 6) From the underside of the breech case insert in the extrac­ Remove the asbestos string packing, oil it and wind loosely tor over the firing pin hole a *live cartridge and raise the around the barrel, and while so doing it should be pushed in extractor to its highest point. with a No. 3 punch or piece of wood which will fit. Now screw *CAUTION.-A live cartridge should only be used on on the gland as tightly as possible by hand. the range or under conditions where it is possible for the The water leak should now be rectified and the recoiling muzzle of the gun to be pointed in the direction of safety, portions should now move quite freely. To test this place the otherwise an armourer's gauge which is made for this gun in a horizontal position, hang the lock and work the recoil purpose should be used. portion backwards and forwards. (7) See that the barrel is home and rotate the crank handle for­ TO CHECK WEIGHT OF RECOILING PORTIONS wards, at the same time guiding the cartridge into the chamber. Remove fuzee spring, place crank handle in nearly vertical (8) If the connecting rod is the correct length a check will be position. Place loop of spring balance on crank shaft and pull felt ( other than pressure necessary to depress the sear) as the slowly to rear. Weight should not exceed 4 lbs. crank handle reaches the check lever. If excess weight is required to move the recoiling portions, (9) If no check is felt the connecting rod should be adjusted as it is caused by the packing pressing too hard on the barrel. The gland should be removed and one or two strands taken out of follows:- the asbestos. Retest recoiling portions for smooth working. Washers of the No. 1 and No. 2 sizes, or both, as required to make the length correct should be placed on the outer face of BROKEN LOCK SPRING the adjusting nut of the connecting rod. Any replacements of parts in the lock should be done in When the correct length has been found in this manner, the sequence as it is stripped. In the case of breakage of the lock washers must now be assembled permanently on the shoulder spring, however, it being possible to shake out the broken of the connecting rod and secured by its nut. To do this unscrew portions clear of the lock, a new lock spring may be assembled and remove the adjusting nut by means of the combination tool, without stripping the lock. See detailed Stripping of Lock and place the washers on the connecting rod, and replace and screw its reassembly, p. 16. up the adjusting nut tightly on to the washers. Retest the connecting tod to ensure the adjustment has been WEIGHING AND ADJUSTING FUZEE SPRING carried out correctly. See " Before Firing," p. 31 para. 3.' TO RENEW DISC ON MUZZLE ATTACHMENT CORRECT PACKING OF GLANDS Unscrew front cone and remove old disc by cutting it and To renew or correct the packing of the glands, the following prizing up a piece which can be gripped by nose of a pair of procedure should be carried out :- pliers, and pull the old disc off. Place new disc in position, and tap it home on to front cone. 22 SIGHTS FORESIGHT A blade foresight is fitted at the top of the barrel casing ; It IS dovetailed into the sight block, and is thereby adjustable later­ ally. It is provided with a tubular foresight protector. BACKSIGHT In Plate X is illustrated the backsight described in detail below. It is to be noted that guns may be fitted with different types of backsights to the one described. The description that follows should enable other types of backsights to be easily understood and used. It consists of a leaf. In its lowered position an open U backsight is in position, which is sighted for 500 metres. When leaf is raised graduations on the leaf are used by which the slide is set to the range required. For large variations in elevation the catch of the right side of the slide is depressed and the slide raised or lowered to range selected. For small and fine adjustments of elevation the elevating notched wheel at the top of the slide is used. The slide carries an adjustable plate con­ taining five different-sized apertures so as to enable the gunner to select the one most suitable to the shooting conditions. To set for the aperture required, push in with the tip of a finger on the serrated circle on the aperture plate and turn until the aperture required is at the bottom. Make sure aperture plate is correctly fixed by seeing that the corresponding notch on the periphery of the sight plate is engaged with the key at Plate X BACKSIGHT the top of the slide. The aperture is set to the range marked on the leaf that 79 Graduated leaf. 84 Six-hole adjustable aperture coincides with the bottom face of the window (e.g. illustration 80 Adjustable backsight slide. eye-piece. 81 Adjustable backsight slide. 85 Windage adjustment screw. shows aperture sight set for 1,200 metres). In addition to the catch. 86 Elevating fine adjustment aperture there is an open U backsight at the top of the slide. 82 Fixed open backsight. screw. This open sight is set to the range marked on the leaf that 83 Adjustable open backsight. coincides with the top edges of the shoulders of this sight (e.1;., illustration shows open adjustable backsight set for 1,550 metres). It will be noticed from the illustration that the grooves in the leaf in which the slide moves up and down incline to the left, so that as the slide _is raised the aperture is automatically moved to the left. This movement is made to counteract the drift of the bullet. gunner, moves sight to left to counteract for wind blowing The leaf sight is mounted on a base which is adjustable for from left to right, and when rotated backwards (i.e., towards windage : this adjustment is accomplished by means of the gunner) the sight is moved to the right to counteract wind milled-head screw situated to the left of the sight base. This blowing from the right. windage adjustment screw, when rotated forwards away from Continued at foot of page 25 24 25 THE TRIPOD MOUNTING 18 88 The tripod with the gun mounted in position is clearly shown in Plates I and II, pp. 5, 7. 89 The crosshead, elevating gear, socket, direction dial, jamming bolts and clutch plates are clearly shown in Plate XI. 90 When the gun is mounted on the tripod, the jamming handle 98 of the rear leg should be adjusted so that the direction dial is horizontal. 19

ELEVATING GEAR To elevate the gun, the hand wheel is turned anti-clockwise. To depress the gun the hand wheel is moved in the opposite 97 direction. ,. The text which follows under the headings " To Erect Tripod," " To Dismount Tripod," " To Mount Gun," should be read as notes on how to carry out these operations ; they are not intended to convey the sequence of drill or the complete drill. The operations carried out by No. I and No. 2 of the gun team are specifically mentioned as they occur in these operations. The duties of other members of the gun team and the drill of the gun team are fully laid down in the official textbook covering this point.

TO ERECT TRIPOD The tripod is placed on the ground, legs folded and to the rear, Plate XI TRIPOD socket upright. 18 Crosshead arm. 91 Front leg clutch plate. Place one leg either side of the legs, bend down and slacken 19 Socket. 92 Front leg jamming handle. off the jamming handles sufficiently to disengage clutch plates. 20 Front leg 93 Crosshead pin. 21 Rear leg. 94 Rear leg jamming handle. Now grasp the arm of the crosshead close to the socket with both 22 Elevation dial and elevating 95 Rear leg clutch plate. hands and raise the tripod the correct height. First let go the handwheel. 96 Elevating tumbler. arm of the crosshead with the right hand, which should now do 88 Crosshead. 97 Elevating pin chain. 89 Direction dial. 98 Elevating gear. up the right front leg jamming handle, and similarly the left 90 Block jamming handle. front leg jamming handle is tightened with the left hand, the 99 E levating pin. right hand meanwhile grasping the arm of the crosshead. The rear leg jamming handle is now clamped up tight, making certain that the socket is upright and so the direction dial will be horizontal. Finally ensure that the tripod legs are firmly on the ground (the spade shoes should be stamped in) and all jamming handles are clamped up tight, the clutch plates being in correct engage­ ment. The tripod should be the correct height for the firer in the sitting position. The rear leg should be in alignment with the target.

26 The erection of the tripod above described is carried out by No. 1 of the gun team on command " Mount gun." When he KINDS OF FIRE has completed the above, he finally removes the elevating and SEARCHING FIRE crosshead joint pin and then sits down in rear of the rear leg Cultivate the ability to turn the elevating wheel so that the line with his legs either side of it. of sight is displaced up or down as required 15 minutes for TO DISMOUNT THE TRIPOD every turn. No. 1 reverses the above procedure described under "To TRAVERSING FIRE Erect Tripod." When completed, both elevating and crosshead Traversing the gun is accomplished by tapping the gun in the joint pins should be correctly inserted and handle turned down. required direction as follows :- The legs should be correctly folded together and the jamming To traverse gun and strike of bullets to right, the right h_and handles done up. No. 1 then lies down to the left of the tripod releases its hold of the right traversing handle and the nght (or stands to attention). hand is made to tap the right traversing handle (with the ball TO MOUNT THE GUN of the thumb, hand open) so that it is driven over to th~ left, No. 2 mounts the gun in the following manner : First the shut­ thus the direction of the muzzle and therefore of the stnke of ter is opened. Pick up gun by grasping t~e right traver~ing the bullets is traversed to the right, and vice versa (left hand handle with the left hand and the barrel casmg under the nght tapping left traversing handle) to traverse gun to left. A regular arm. By kneeling on the left knee and extending the right leg tap should be cultivated so that, together with the clamp forward, the gun can be placed in position on the t~ipod, ~nd adjusted to a nicety, each tap will move the line of sight No. 2 now, by supporting the barrel casing on the nght t~1~h, 15 minutes. Note it is far preferable to employ a strong tap can with his right hand grasp the handle of the crosshead Jomt with the clamp tight than a weak tap with a loose clamp. pin and, with it turned upwards, drive it in and home ; the handle of this pin is now turned down. No. 2 now releases OBLIQUE TRAVERSING hold with his left hand of the right traversing handle, pulls out Oblique traverse is carried out by combining traversing with an the cork plug and affixes steam pipe and inserts its end in the alteration of the elevating wheel. condenser. It is of importance that the necessary actions to accompJish FIRING THE GUN an oblique traverse are carried out in the correct sequence, i.e. : FIRING POSITION (A) Fire-TAP-elevate (or depress). With gun correctly mounted on tripod as previously described (B) Tapping should be automatic as in ordinary traverse. and the rear leg in alignment with the target, No. I should be (c) When the gun is elevated or depressed, the sights should seated on the ground in rear of the rear tripod leg, his legs be used, as the amount of movement of the handwheel will either side of the rear tripod leg ; feet inclined outwards? knees depend upon the angle which the line to be traversed makes slightly drawn up so that, with the hands correct!)'. g~aspmg the with the horizontal. Thus the greater this angle the larger traversing handle, the elbows can rest on the ms1de of the amount of movement required by the handwheel. (Do not con­ thighs. . . . . fuse this alteration of the elevating wheel with the regular With the gun at the correct height this position should be 15-minute regular alteration employed in searching previously comfortable and free from strain and the eye should be on a described.) level with the line of sight. HOW TO HOLD TH~ TRAVERSING HANDLES SWINGING TRAVERSE OPERATING THE SAFETY CATCH AND THUMB-PIECE The swinging traverse is only used at very close ranges against The third and little fingers should be grasped round the particular vulnerable targets needing a large amount of total traversing handles, the thumbs resting lightly on the thumb­ traverse, when the normal method of traversing the gun would piece, the second fingers behind the safety catch and the fore­ be too slow. fingers on top of the traversing handles. It is important that the crosshead should be kept upright. 28 29 Take up the normal firing pos1t10n, both hands on the traversing handles. The body should be held fairly rigid and FIRING the gun traversed by moving the forearms and body, over to the left to traverse the gun to the right, and over to the right to BEFORE FIRING traverse the gun to the left. The following points should be attended to before firing :- The rate of swing imparted to the gun in this manner is 1. EXAMINE BARREL scarcely perceptible but rather felt as the gun vibrates. It 2. OIL UP should be such as to alter the line of sight at the target at a range of 25 yards by 3 feet for every ro to 20 shots fired (approximately All moving parts should be thoroughly well oiled with a good one and a half to two seconds' continuous fire). lubricating oil. As soon as the gun begins to move on to the target the thumb­ Pay particular attention to the following :- piece should be pressed. The recoiling portions-bearing parts of the barrel, side plates, lock guides on the side plates, all working parts of the TO LAY THE GUN lock, extractor guides and levers and bearings of the crank, On the target being indicated, No. I will tap the gun over until connecting rod and side levers. Recess in prolongation of left the correct direction is obtained, then elevate or depress the side plate. gun until the aim is correct. Covers-extractor stop in front cover, extractor ramps, trigger bar, cover catch and lock guides in rear cover. ADJUST SIGHTS Feed Block-bottom lever stud, top lever stud, slide. See pages 24 and 25. Fuzee and chain. Check lever. "FIRE" 3. WEIGH FUZEE SPRING On being given the signal or command to fire, No. I will press in the thumb-piece with his thumb (having raised the safety Check weight of fuzee spring as follows : Take out lock. Loop catch with the second finger) as far as it will go; this should be spring balance over crank handle and press down check lever. done with a quick and even movement. The thumb-piece is Weight indicated when crank handle begins to move, 7 to 9 lbs. released after the required number of rounds have been fired in Adjust by means of vice pin. Six clicks make difference of I lb. the burst of continuous fire resulting, and again the thumb-piece Clockwise increases, anti-clockwise decreases. is depressed for the next burst, and this is repeated as ordered. 4. TEST FOR SMOOTH AND CORRECT WORKING OF Normal bursts are from 10 to 20 rounds, or approximately two MECHANISM seconds. The recoiling portions should be checked to see that they work freely. To test this, remove the fuzee box and chain, turn the " CEASE FIRE" crank handle to the vertical position, and with it so held move The pressure on the thumb-piece and safety catch will be at the recoiling parts backwards and forwards. They should work once released. Aim should be immediately checked and any freely and the barrel should go thoroughly home in its forward faults found with same corre·cted. position. The weight necessary to move the recoiling portions should not exceed 4 lbs. Replace fuzee spring. Rotate the EYES crank handle two or three times, and check to see that the When the gun is being fired, the eyes should be directed at the mechanism is functioning correctly. Raise safety catch and target the whole time. They should not be allowed to look at press thumb-piece to ensure correct functioning of the firing the thumb-piece when being pressed or the movements made mechanism. Ensure correct functioning of feed block. The by either hand when traversing. muzzle cup should be quite dry and firmly screwed on. Thoroughly dry the bore and muzzle attachment.

30 5, PACKING GLANDS 6. BELT FEED The front and rear packing glands should make a watertight fit Keep belt always in line with feed block, and if possible the with the barrel and muzzle gland and the barrel and the ammunition box should be kept up to but not above the cross­ trunnion block respectively, and at the same time allow the head joint pin. barrel to reciprocate smoothly on the forward and backward 7. DURING TEMPORARY CESSATION OF FIRE movement of the recoiling portions. Take the opportunity to :- 6. WATER SUPPLY (A) Change partly used ammunition belt for full one. Fill the barrel casing with water by removing the screw filler (B) Oil mechanism. plug at the rear end and removing the cork steam plug at the (c) Check tripod mounting for rigidity; see that clamps have front end of the casing. not worked loose and are quite tight. With the casing filled with water there should be no water (n) See that muzzle cup is tight. leaks at the front packing gland or the trunnion block where the AFTER FIRING barrel protrudes ; the latter point can be observed by removing The foilowing points should be attended to after firing - the feed block. (1) Unload gun. Attach condenser tube and insert free end in condenser. (2) Oil chamber, bore and muzzle cup attachment immediately 7. SUPPLY OF OIL IN HANDLE upon cessation of firing. (3) Release lock spring. Unscrew the milled heads (to which oiling brushes are attach~d) (4) Collect any live cartridges that may be amongst the empty on the traversing handles, and see that the latter are filled with cases. oil. (5) On return to quarters­ NoTE.-Re 4, 5, 6 above refer to pp. 22 and 23 for correct (A) Drain casing of water. adjustment. (B) Remove barrel, clean outside and grease before reassem­ DURING FIRING bling. The following points should be attended to during firing :- (c) Thoroughly clean *bore of barrel, using hot water, 4x2, and oil in the approved manner as for a rifle, preferably using a 1. WATER SUPPLY cleaning rod ; leave bore thoroughly well oiled. The barrel casing should be kept well supplied with water so (o) Exatnine all parts, thoroughly clean and oil. that the barrel is always covered. (See p. 35, for data re water (E) Examine ammunition belts, which should be cleaned if consumption.) dirty. Hang up to dry if damp. Repair if torn. (F) Clean tripod and oil working parts. 2. DO NOT PULL BELT *N0TE.-The bore of the barrel is usually cleaned from the The ammunition belt should never be pulled when the gun is muzzle end, when assembled in the gun. To do this, first firing. remove the lock in order that the face of the extractor cannot 3. OIL MECHANISM get damaged by the end of the cleaning rod being driven against Every opportunity should be taken to see that mechanism is kept it. Remove muzzle attachment and muzzle cup (which can well oiled. • now be cleaned also and should be left oiled). With flannelette on the jag, the cleaning rod may be inserted in the muzzle, 4. REFILL AMMUNITION BELTS placing the movable bush on the muzzle, and the rod worked Empty or partly used ammunition belts should be refilled up and down the bore. (If no movable bush is available, take without delay. care to avoid muzzle wear, or the bore may be cleaned from the breech end. When the barrel is removed for carrying out (c) 5, TRIPOD above, it is then best to pour hot water down the bore prior Watch tripod mounting for rigidity and tightness of clamps. to carrying out the above. Alternatively, a funnel may be used and inserted at the breech end.) 32 33 IMMEDIATE ACTION cartridges are not inserted, and if the connecting rod is adjusted to the On the Vickers gun (or any other gun for that matter) never think in correct length, failure in the second position will not occur. terms of " stoppages." If the gun is properly looked after by the " No. I " and the points before, during and after firing attended to POSITION III IMMEDIATE ACTION to be taken to rectify the " stoppages' will seldom occur. ' stoppage that has ?ccurr~<;i as indicated by It _is IMMEDIATE ACTION which must be studied. Learn it as a tht" crank handle m Position III. drill so _th~t it c~n be applied instinctive)y and at once should the gun Slightly raise the crank handle, give the stop finng or fail to fire. The great ma1ority of the causes which call c· belt a sharp tug to the left and by a · V, glancing blow with the palm of the hand for immediat~ action are preventable if the gun is " serviced " with care. When the Vickers gun is firing the crank handle is moving backwards strike the crank handle down on to its and forwards and rotating continuously. It is the position in which the bed on the check lever. If the crank handle crank handle stops that indicates to the gunner the kind of immediate does not go down, glance at or feel the feed block slide. If the slide is action to be applied. In daylight the position can at once be seen, and wedged pull the crank handle on to the roller (" No. 2 " may have to assist at night the position in which it has stopped can be felt with a touch of by opening the front cover and forcing down the horns ofthe extractor) and the hand. " hold it there. " No. 2 " must lift up the feed block sufficiently to allow I~edi~te action, in a slightly different form in each case, must be the recoiling portions to go home, release the pawls and withdraw the applied if the crank handle stops in any of four positions shown in the belt enough to allow the uneven cartridges to be rectified and the belt illustrations. straightened. Replace feed block, close and lock front cover, give the belt a sharp tug to the left, let go crank handle, relay the gun and carry POSITION I IMMEDIATE ACTION to b_e taken to rectify on firing. If the slide is free " No. 2 " must open the front cover, force 0 the stoppage that has occurred as indicated down the horns of the extractor and at the same time " No. I " must by the crank handle in Position I. pull the crank handle on to the roller. "No. 2" will remove the first Pull the crank handle on to the roller, cartridge in the belt, and " No. 1 " will change the lock, reload, relay and give the belt a sharp tug to the left, let go carry on firing. crank handle, relay and carry on firing. NoTE.-See that the belts are evenly filled and are up and in line with the If after firing, stoppage recurs, with the feed block ; that the pockets are not worn or loose ; that no thick-rimmed crank handle in the same position, carry cartridges are inserted in the belt and failure in the third position will not out the Immediate Action again and lighten occur unless the cause is due to a faulty or broken extractor. fuzee spring by half a pound. Relay and carry on firing. POSITION IV IMMEDIATE ACTION to be taken to rectify the NoTE.-Keep the gun free of excessive friction and grit; see that the stoppage that has occurred as indicated by pockets in the belt are not too tight, that the glands are properly packed, the crank handle in Position IV. and that the weight of the fuzee spring is set at the gun's " pet " weight. Pull the crank handle on to the roller, give If this is done failure in the first position will not occur unless the cause the belt a sharp tug to the left, let go is due to faulty ammunition and consequent weak explosion, a rare crank handle, relay and carry on firing. If occurrence. gun fails to fire, repeat. If gun still fails POSITION II IMMEDIATE ACTION to be taken to rectify the to fire, pull the crank handle on to the stoppage that has occurred as indicated i,y roller twice, change the lock, reload, relay and carry on firing. the crank handle in Position II. Pull the crank handle on to the Roller, lift up NoTE.-Except for an empty pocket in the belt, failure in the fourth the rear cover and raise the lock. Examine the position will not occur unless the cause is due to detective ammunition cartridge on the face of the extractor. If it is a or a broken or faulty part of the lock. damaged cartridge or an undamaged cartridge REMEMBER, immediate Action is not completed until the gun has with the front portion of a separated case been relaid on the target and the thumb-piece pressed. adhering to it, clear the face of the extractor, reload, relay and carry on firing. If it is not a Q damaged cartridge or if the front portion of a DISTINGUISHING MARKS separated case is not adhering to an undamaged . cartridge, call for clearing plug. Insert this To distinguish it from the .303 calibre gun all .300 calibre Vickers guns :nto the breech, extract the front portion of the separated case which is should have the following parts painted red: Front body cover (2 in. causing the obstruction, reload, relay and carry on firing. band), mouth of feed block, side lever head. NoTE.- If care is taken when the belt is filled to see that damaged

34 35 USEFUL NOTES CONSERVATION OF WATER On active service replenishments of water supplies are sometimes either unavailable or there is no time for them to be brought up to gun position. In order to conserve water and save time, the following procedure can be adopted when it is necessary to withdraw the recoiling portions and barrel from the gun for reasons such as replacements, faulty or broken parts, adjustments or examination. Ensure gun is unloaded. (r) No. 2 of the gun team removes from gun the muzzle attachment·and unscrews muzzle cup from barrel. (2) A plug should be previously prepared the size of the barrel at the muzzle end and of a length that will effectively seal the muzzle gland on the barrel being withdrawn. A temporary plug can be quickly prepared by using a spent cartridge case wrapped round with flannelette. (3) No. 2 places this plug against the muzzle of the barrel and, when the barrel is withdrawn by No. r, follows the barrel with the plug so that, as the barrel recedes from the muzzle gland, the plug effectively seals the gland. While all the above operations are being carried out by No. 2, No. r removes the elevating pin and depresses gun. (No. 2 holds the gun thus depressed at an angle which will ensure that no water will flow out of the rear of the barrel casing through the trunnion block when the barrel is withdrawn.) When the necessary replacements of parts, repairs or examination have been undertaken by No. r, he reassembles the gun, and as the barrel is pushed forward home it pushes out the plug in the muzzle gland. No. 2 now reassembles muzzle cup and muzzle attachment. When the barrel is replaced it is advisable to plug muzzle with piece of flannelette to prevent water running down bore. Finally, when gun is reassembled, the piece of flannelette plugging muzzle should of course be removed ; and to ensure bore being clean, no water or obstruction being left, flannelette patch should be run through the bore on the cleaning rod. During these operations No. 2 should take care that hot water does not reach his hands, as it may be ·quite hot enough to cause nasty scalds. If there is time to drain the water jacket, this is done by removing the filler plug to allow air to enter, thus accelerating flow of water, and removing the drain plug and allowing water to flow into condenser can. CONVERSION TABLE METRES INTO YARDS YARDS INTO METRES 2,000 metres 2,200 yards 2,000 yards 1,800 metres 1,000 ,, 1,100 ,, I ,ooo ,, 900 ,, 750 " 825 " 750 675 ,, 500 " 550 '! 500 " 450 " 200 ,, 220 ,, 200 ,, 180

WATER CONSUMPTION Water boils after firing approximately 500 rounds continuously. Water evaporates at the rate of about r½ pints per 500 rounds fired continuously. After firing approximately 2,000 rounds the barrel casing will require refilling. The gun may be fired up to 1,000 rounds (in special circumstances) without water in the jacket. · LOG BOOK It is very important that a log book be kept for each gun, recording its details, number of rounds fired, etc. Details of such a book can be obtained from Gale & Polden Ltd.